La niñera habla suavemente cuando la niña tiene una rabieta.

In Spanish, the definite article (el, la, los, las) is used more often than the is in English.

Here, la niñera means the nanny and la niña means the girl. In a complete sentence, Spanish often includes the article before common nouns when talking about a specific person or thing.

So:

• La niñera = the nanny
• la niña = the girl

This sounds completely natural in Spanish, even if English might sometimes leave the out in similar contexts.

They look similar, but they mean different things:

• niña = girl
• niñera = nanny / babysitter

The ending -era often turns a noun into a person associated with a job or role. So niñera is a person who looks after children.

Be careful not to confuse them:

• la niña = the girl
• la niñera = the nanny

Habla is the present tense of hablar and is often used for:

• habits
• repeated actions
• general descriptions
• what usually happens

So La niñera habla suavemente cuando la niña tiene una rabieta suggests a usual pattern: whenever the girl has a tantrum, the nanny speaks softly.

Spanish uses the simple present more often than English does in this kind of sentence.
Está hablando would emphasize that the action is happening right now, at this moment.

So:

• habla = speaks / does speak / is speaking, depending on context
• está hablando = is speaking right now

Because adverbs in Spanish often come after the verb, especially adverbs of manner like suavemente (softly / gently).

So:

• habla suavemente = speaks softly

This is the most natural word order here.

English also often does this:

• She speaks softly

So this part matches English fairly well.

Suavemente comes from the adjective suave, meaning soft / gentle / smooth.

To form many adverbs in Spanish, you add -mente to the feminine form of the adjective:

• suave → suavemente

This works like English -ly in many cases:

• rápido → rápidamente
• lento → lentamente
• suave → suavemente

So suavemente means softly, gently, or in a gentle way.

Because Spanish commonly uses the expression tener una rabieta, which literally means to have a tantrum.

It is an idiomatic expression:

• tener = to have
• una rabieta = a tantrum

So:

• La niña tiene una rabieta = The girl has a tantrum / is having a tantrum

English also uses have a tantrum, so this structure is actually quite similar.

Rabieta means tantrum, especially a child’s angry outburst.

It suggests behavior like:

• crying
• shouting
• stamping feet
• getting very upset in a childish way

In Spain, rabieta is a very common word for this idea.

Because rabieta is a countable noun here. The expression is tener una rabieta = to have a tantrum.

Just as English says:

• have a tantrum

Spanish says:

• tener una rabieta

Leaving out una would sound unnatural in this sentence.

Because this sentence describes something habitual or generally true.

Cuando can be followed by different verb forms depending on meaning:

• present indicative for repeated, habitual, or known situations
• subjunctive for future or uncertain situations

Here, the meaning is:

• Whenever the girl has a tantrum, the nanny speaks softly.

That is a repeated situation, so the present indicative is correct:

• cuando la niña tiene una rabieta

If you were talking about a future event, you might use the subjunctive:

• Cuando la niña tenga una rabieta, hablaré con ella con calma.
• When the girl has a tantrum, I’ll speak to her calmly.

It is closest to tantrum.

It is not just a general bad mood, and it is not simply the emotion of anger. It refers more to the visible outburst or fit, especially in a child.

So:

• enfadada = angry
• de mal humor = in a bad mood
• con una rabieta / tiene una rabieta = having a tantrum

A few helpful points:

• ñ is pronounced like ny in canyon
• niña sounds roughly like NEE-nya
• niñera sounds roughly like nee-NYE-ra
• rabieta sounds roughly like ra-BYE-ta

Stress:

• niña → stress on the first syllable
• niñera → stress on -ñe-
• rabieta → stress on bie

Also, h in habla is silent:

• habla sounds roughly like AH-bla

It can mean nanny or babysitter, depending on context.

In many cases:

• niñera = someone who looks after children
• nanny may fit if it is a regular caregiver
• babysitter may fit if it is more occasional

In Spain, you may also hear canguro for babysitter, especially in everyday speech.

So niñera is a good general word, but the exact English translation can vary with context.

Yes, you could. It means something very similar.

Compare:

• habla suavemente = speaks softly / gently
• habla con suavidad = speaks with gentleness / gently

Both are correct.
Suavemente is a simple adverb form, while con suavidad uses a noun phrase.

In this sentence, habla suavemente is very natural and concise.